The present disclosure relates to heat sealed packaging useful in applications requiring a high degree of dimensional stability at elevated oven temperatures.
For the convenience of consumers, packaged food may be designed to be placed directly in a microwave or conventional oven to heat or cook the food without first removing the packaging. The consumer thus avoids having to handle the raw product or to clean a container in which the food would have otherwise been placed for cooking or heating. The consumer may also simply dispose of the packaging material after heating or cooking the food.
Packaging that can withstand exposure to the heating and/or cooking environment of a selected type of oven is said to be “ovenable” with respect to that type of oven. To be ovenable with respect to a microwave oven, the packaging should not, for example, include materials such as metals that reflect microwaves to cause arcing or otherwise damage the oven's microwave generation. To be ovenable with respect to a conventional oven, the packaging should be able in use to withstand exposure to an elevated temperature (e.g., 375° F. or 400° F. air temperature) for an extended period of time (e.g., three hours) while maintaining desired performance attributes. Packaging that is ovenable both with respect to a microwave oven and a conventional oven is said to be “dual-ovenable.”
Ovenable packaging may subjected to handling and loading forces associated with distribution of the package, which begins almost as soon as the package has been created. For example, such forces may be encountered by the packaging before the polyamide present in the packaging film of the package has had the opportunity to equilibrate with ambient moisture (i.e., humidity). It is desirable that such forces not cause leaks or other failures in the packaging.